PS11-20 Virtual fencing of rangeland cows during late lactation and following weaning

Authors: UTSUMI, S - New Mexico State University; NYAMURYEKUNG'E, S - New Mexico State University; PEREA, A - New Mexico State University; SPETTER, M - New Mexico State University; COX, A - New Mexico State University; Macon, Lara; Estell, Richard - Rick; DUFF, G - New Mexico State University

Submitted to: Journal of Animal Science Supplement
Publication Type: Other
Publication Acceptance Date: 4/17/2023
Publication Date: 11/6/2023
Citation: Utsumi, S.A., Nyamuryekung'E, S., Perea, A.R., Spetter, M., Cox, A., Macon, L.K., Estell, R.E., Duff, G. 2023. PS11-20 Virtual fencing of rangeland cows during late lactation and following weaning. Journal of Animal Science Supplement. 101:Abstract.

Interpretive Summary: Virtual fencing is a promising alternative to contain livestock dispersal without using physical barriers. This technology uses smart-wearable collars that deliver predictable warning tones to animals when they approach virtual boundaries paired with mild electric pulses. Virtual fencing allows for dynamic management of livestock grazing, based on site-specific variations in the quality and quantity of forages. However, several factors can affect the efficacy of virtual fencing, including the length of prior experience with virtual fencing, climatic conditions, forage availability inside and outside virtual fencing paddocks and collar configuration schedules. Lactation requirements and social interactions between collared cows and uncollared calves can also influence the efficacy of the technology. Virtual fencing trials were conducted at the New Mexico State University’s Chihuahuan Desert Rangeland Research Center from August 27 to December 21 of 2022 to evaluate the efficacy of virtual fencing to manage rangeland cows during late lactation and following weaning. Twenty-six Brangus cows previously trained to use NoFence C2 collars (NoFence, Batnfjordsøra, Norway), were monitored for 30 days during late lactation and 28 days after weaning. Collared cows and uncollared calf pairs were allocated to four virtual fence pastures in late lactation and after weaning, with pasture duration (4.2 ± 0.6 d), size (72 ± 19 ha) and perimeter (4,523 ± 352 m) varying according to forage availability and access to fresh drinking water. Audio cues, electric pulses and ratio of electric pulses to audio cues before and after weaning were compared by ANOVA in a Completely Randomized Design replicated across pre-weaning and post-weaning pastures (n = 8). The average number of electric pulses per cow was greater (P < 0.0004) for pre-weaning (3.7 ± 0.2) than for post-weaning post-weaning (1.6 ± 0.3) pastures. The number of audio warnings per cow was also greater (P < 0.0001) for pre-weaning (52 ± 3.3) than post-weaning (34 ± 3.3) pastures. Conversely, cows had decreased (P < 0.0001) ratios of electric pulses relative to audio tones on post-weaning (4.8 ± 0.5%) than pre-weaning (7.0 ± 0.8%) pastures. These results suggest that cows responded better to virtual fencing after weaning, likely because weaned cows were no longer affected by social interactions with uncollared calves. Furthermore, cows after weaning apparently relied on warning tones and fewer electric pulses to interact safely with virtual fences. However, it is important to note that sources of variation not accounted for or controlled by the present experimental design may have also affected the recorded interactions with virtual fences in the present study.

Technical Abstract: Virtual fencing can be used to replace physical barriers for livestock containment through the use of smart-wearable collars programmed to deliver predictable tones to warn animals of their proximity to virtual boundaries paired to mild electric pulses. Virtual fencing is a promising approach to dynamically manage livestock grazing based on site-specific variations in the quality and quantity of forages. Prior experience with virtual fencing, climatic factors, forage availability and collar configuration schedules are potential sources of variability for use of virtual fencing. Lactation requirements and social interactions between collared cows and uncollared calves can also influence the efficacy of virtual fencing. Virtual fencing trials were conducted at the New Mexico State University’s Chihuahuan Desert Rangeland Research Center from August 27 to December 21 of 2022 to evaluate the efficacy of virtual fencing to manage rangeland cows during late lactation and following weaning. Twenty-six Brangus cows previously trained for using NoFence C2 collars (NoFence, Batnfjordsøra, Norway) were monitored for 30 days during late lactation and 28 days after weaning. Collared cows and uncollared calf pairs were allocated to four virtual fence pastures in late lactation and after weaning. Pasture duration (4.2 ± 0.6 d), size (72 ± 19 ha) and perimeter (4,523 ± 352 m) varied according to forage availability and access to fresh drinking water. Audio cues, electric pulses and ratio of electric pulses to audio cues before and after weaning were compared by ANOVA in a Completely Randomized Design replicated across pre-weaning and post-weaning pastures (n=8). The average number of electric pulses/cow was greater (P< 0.0004) for pre-weaning (3.7 ± 0.2) vs. post-weaning (1.6 ± 0.3) pastures. The number of audio warningss/cow was also greater (P< 0.0001) for pre-weaning (52 ± 3.3) vs. post-weaning (34 ± 3.3) pastures. Conversely, cows had lower (P< 0.0001) ratios of electric pulses relative to audio tones on post-weaning (4.8 ± 0.5%) vs. pre-weaning (7.0 ± 0.8%) pastures. Results suggest that observed responses of cows to virtual fencing improved for post-weaning vs. pre-weaning pastures likely because weaned cows were no longer affected by social interactions with uncollared calves. Furthermore, cows after weaning apparently relied on warning tones and fewer electric pulses to interact safely with virtual fences. However, sources of variation not accounted or controlled by the present experimental design may have also affected the recorded interactions with virtual fences in the present study.